The present invention relates to a cantilever probe and a method of manufacturing the same, and more particularly to a cantilever probe and a method of manufacturing the same suitable for a scanning type probe microscope represented by the AFM (Atomic Force Microscope). Further, to describe more specifically, the present invention relates to a cantilever probe and a method of manufacturing the same in which a probe approaching the surface of a sample to be scanned thereby is provided at a free edge of the cantilever and a beam section thereof is deflected by force generated between the probe and the surface of the sample. Also, the present invention relates to observation, when a surface of a sample existing in a liquid is to be observed, of the surface of the sample with an optical lever reflecting section of the cantilever probe kept above the liquid. The present invention also relates to a scanning type probe microscope utilizing the cantilever probe.
A cantilever with a probe provided at a free edge of a beam section thereof supported in a cantilever form has been used as a scanning probe in a scanning type atomic force microscope (AFM). In the cantilever probe having the configuration as described above, when a surface of a sample is scanned with the probe, an attractive force or a repulsive force according to an interatomic force is generated between the sample surface and the probe, so that a form of the sample surface can be measured by detecting the interatomic force as a deflection rate of the cantilever.
A conventional type cantilever probe for an AFM is disclosed in, for instance, Japanese Patent Laid-Open Publication No. HEI 5-196458, in which the cantilever probe 30 has a linear form as a whole as shown in FIG. 5A and both a free edge 30b at which a probe 1 is formed and a fixed edge 30c fixed to a main body of a microscope are present on an extension line of a beam section 30a of the cantilever. However, when the linear cantilever 30 as described above is used for a scanning probe, if the cantilever is arranged in a posture that the beam section 30a is parallel to the surface of a sample, the beam section 30a may contact the surface of the sample if the sample has a largely wavy surface, whereby the probe 1 can not accurately trace the surface of the sample. For this reason, the cantilever probe 30 based on the conventional technology was attached to the main body thereof at an angle, as shown in FIG. 5B, toward the surface of a sample so that the probe 1 can accurately trace the surface thereof without contacting of the beam section 30a with the sample 20 even if the sample has a largely wavy surface.
Also, when a sample in a liquid is to be measured with the conventional type AFM, an entire cantilever probe is required to be sunk in the liquid and a lever section as a reflecting surface of an optical lever is also in the liquid, which makes it difficult to adjust a position of a laser, or a reflecting position is changed due to its refraction, absorption, or change in a liquid surface, so that reflection intensity becomes weaker or accurate measurement can not be carried out.
As described above, when the cantilever probe 30 is attached at an angle toward a surface of a sample, the probe 1 approaches the surface of the sample also at an angle toward it. FIG. 6 is a simulated view showing an interatomic force when the probe 1 approaches the surface thereof at an angle toward it, and it is clear that the interatomic force does not uniformly apply to to the probe 1 in the posture shown in the figure. For this reason, a deflection rate of the cantilever probe 30 cannot accurately represent a distance between the probe 1 and the sample 20, so that the sensitivity is reduced and a measurement error becomes larger. Also, when a sample in a liquid is to be measured, as the entire cantilever probe is sunk in the liquid, a laser for detecting an optical lever is reflected on a liquid surface or absorbed by the liquid, and also reflection intensity of a laser drops or a reflecting position is displaced, which makes it impossible to perform correct or high sensitivity detection.
The present invention was made for solving the problems relating to the conventional technology, and it is an object of the prevent invention to provide a cantilever probe and a method of manufacturing the same in which, even if a probe formed at a free edge vertically approaches a surface of a sample to be scanned thereby, the probe can accurately trace the surface thereof with the main body of the cantilever probe not contacting the surface thereof. Further, it is another object of the present invention to provide a cantilever probe and a method of manufacturing the same in which accurate observation of a sample in a liquid can be performed, when a sample in a liquid is to be observed, because a laser reflecting surface of the cantilever does not sink in the liquid. Another object of the present invention is to provide a scanning type probe microscope utilizing the cantilever probe.